Fabrication of items of manufacture to specific circumferential dimensions efficiently is essential for maximizing profitability, especially for those produced by hand, for example, woodturnings on a lathe. Currently, mechanical calipers are preset to the desired dimensions and used to check the item during manufacture for achieving final dimensions. Measuring the diameter of a circular cross section of an item, particularly while it is in motion during manufacture without resetting a caliper or using multiple ones would greatly increase efficiency and profitability. Thus, there is a need for calipers and methods to automatically measure circumferential dimensions of items in motion or stationary during manufacture.